Gas streams comprising sulfur species, in particular hydrogen sulfide (H2S), originate from various sources. Natural sources of hydrocarbons may comprise hydrogen sulfide, and hydrogen sulfide is a common additive which provides odour to commercial hydrocarbon supplies. In addition, hydrogen sulfide is often present in waste gas streams from industrial processes.
Sulfur compounds, and in particular hydrogen sulfide, have deleterious effects on many chemical processes. The catalysts used in hydrocracking, synthesis gas processing, methanation, reforming, steam reforming and hydrogenation are often poisoned by the presence of H2S. To avoid these deleterious effects, methods are required which can effectively remove sulfur compounds, particularly H2S, without significant effects on other chemical processes. Most suitable are catalytic methods for sulfur removal.
In addition, during gasification of hydrocarbon fuels to synthesis gas, separation of CO2 and H2S is carried out in an acid gas removal unit. This should take place such that the resulting CO2 stream is pure, and such that the H2S stream does not contain too much CO2.
WO 2010/048201 discloses a process for the removal/recovery of sulfur from a gas stream.
U.S. Pat. No. 4,582,819 discloses a novel catalytic absorbent composition which is useful for removing hydrogen sulfide.
Kiuchi H. et al. Int. J. Hydrogen Energy, Vol. 7, No. 6, pp. 477-482, 1982, disclose a method in which H2S reacts with metal or metal sulfide. The resulting sulfide goes then through thermal decomposition or oxidation at high temperature, i.e. 600° C. and under significant production of Ag2SO4. Schultz et al. Int. J. Hydrogen Energy, Vol. 10, No. 7/8, pp. 439-446, 1985, discloses in a more generic way and with reference to Kiuchi H. et al. also a method in which H2S reacts with metal or metal sulfide, and the resulting sulfide goes then through thermal decomposition or oxidation.
Additional publications in this field include: US2010/0233054, WO 00/02645 as well as JP2010051858A, JP2009185792A, U.S. Pat. No. 5,451,268 and S. Lilienfeld et al, Journal of the American Chemical Society, Vol. 52, No. 3, 1 Mar. 1930, pp. 885-892.
Despite recent advances in the field, there remains a need for a simple, effective method for removal of hydrogen sulfide from a gas stream, preferably in a catalytic process, and preferably with the production of industrially-useful by-products.